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The chosen font must contain the characters that are to be displayed. It can be checked with the Character map on Windows, for example.
Some foreign characters may have a larger vertical size than english ones, so if the characters have to be displayed in a table, the size of the cells must be set accordingly.
There is a known issue within Acrobat, dealing with listboxes and Chinese characters. Details can be found on the following page:
http://www.deskdr.com/dr/acrobat-pro-with-acroform-the-listbox-event-changeex-with-chinese-text-issue.html